Three experiments investigated the effects of information reduction and number of internal transformations in determining task difficulty. The primary dependent variable examined was pupil dilation. In Experiment 1, pupil size was found to increase with increases in amount of information reduction. However, number of internal transformations was confounded with information reduction. In Experiment 2, when information reduction was held constant, it was found that increasing the number of internal transformations resulted in increased pupil size. In Experiment 3, when number of internal transformations was held constant but amount of information reduction was varied, no differences in pupil dilation were found. It was concluded that the usual increase in task difficulty observed with increases in information reduction is due to increases in the number of internal transformations that must be performed.
Task Difficulty Pupil Dilation Pupil Size Error Score Male Voice
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